Fix Volume slider is captured in screenshot done in touchview mode

ash/wm/power_button_controller.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/wm/power_button_controller.h"
 
 #include "ash/common/accelerators/accelerator_controller.h"
 #include "ash/common/ash_switches.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shell_window_ids.h"
+#include "ash/common/system/tray/system_tray_notifier.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/common/wm_shell.h"
 #include "ash/shell.h"
 #include "ash/wm/lock_state_controller.h"
 #include "ash/wm/session_state_animator.h"
 #include "base/command_line.h"
+#include "base/task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/display/types/display_snapshot.h"
 #include "ui/events/event_handler.h"
 #include "ui/wm/core/compound_event_filter.h"
 
 #if defined(OS_CHROMEOS)
+#include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #endif
 
 namespace ash {
 
+namespace {
+const int kWaitVolumeSliderHiddenInMs = 200;

[Daniel Erat, 2016/07/28 04:45:00]

this isn't good; it means there's a delay between when the user requests the
screenshot and when we take it. how long does it actually take for the volume
slider to be hidden? is there an animation that you're waiting for? if so, can
you skip the animation? or is the problem that you're waiting for the screen to
be redrawn?

[Qiang(Joe) Xu, 2016/07/28 20:25:02]

done by disable hiding animation.

+}  // namespace
+
 PowerButtonController::PowerButtonController(LockStateController* controller)
     : power_button_down_(false),
       lock_button_down_(false),
       volume_down_pressed_(false),
+      saved_volume_percent_(0),
       brightness_is_zero_(false),
       internal_display_off_and_external_display_on_(false),
       has_legacy_power_button_(
           base::CommandLine::ForCurrentProcess()->HasSwitch(
               switches::kAuraLegacyPowerButton)),
 #if defined(OS_CHROMEOS)
       enable_quick_lock_(base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kAshEnableTouchView)),
 #else
       enable_quick_lock_(false),
@@ skipping 31 matching lines @@
   // Avoid starting the lock/shutdown sequence if the power button is pressed
   // while the screen is off (http://crbug.com/128451), unless an external
   // display is still on (http://crosbug.com/p/24912).
   if (brightness_is_zero_ && !internal_display_off_and_external_display_on_)
     return;
 
   if (volume_down_pressed_ && down &&
       WmShell::Get()
           ->maximize_mode_controller()
           ->IsMaximizeModeWindowManagerEnabled()) {
-    WmShell::Get()->accelerator_controller()->PerformActionIfEnabled(
-        TAKE_SCREENSHOT);
+    // Notify that maximize mode screenshot is going to be taken. Receiver does
+    // preparation work.
+    WmShell::Get()
+        ->system_tray_notifier()
+        ->NotifyWillTakeScreenshotInMaximizeMode();
+    base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+        FROM_HERE, base::Bind(&PowerButtonController::TakingScreenshot,
+                              base::Unretained(this)),
+        base::TimeDelta::FromMilliseconds(kWaitVolumeSliderHiddenInMs));
     return;
+
+#if defined(OS_CHROMEOS)
+    // Restore volume.
+    chromeos::CrasAudioHandler* audio_handler =
+        chromeos::CrasAudioHandler::Get();
+    DCHECK(audio_handler->IsInitialized());

[Daniel Erat, 2016/07/28 04:45:00]

you don't need this; Get() on the previous line already has a CHECK() that it's
initialized

[Qiang(Joe) Xu, 2016/07/28 20:25:02]

Done.

+    audio_handler->SetOutputVolumePercent(saved_volume_percent_);
+#endif
   }
 
   const SessionStateDelegate* session_state_delegate =
       WmShell::Get()->GetSessionStateDelegate();
   if (has_legacy_power_button_) {
     // If power button releases won't get reported correctly because we're not
     // running on official hardware, just lock the screen or shut down
     // immediately.
     if (down) {
       if (session_state_delegate->CanLockScreen() &&
@@ skipping 48 matching lines @@
   if (power_button_down_)
     return;
 
   if (down)
     controller_->StartLockAnimation(false);
   else
     controller_->CancelLockAnimation();
 }
 
 void PowerButtonController::OnKeyEvent(ui::KeyEvent* event) {
-  if (event->key_code() == ui::VKEY_VOLUME_DOWN)
+  if (event->key_code() == ui::VKEY_VOLUME_DOWN) {
     volume_down_pressed_ = event->type() == ui::ET_KEY_PRESSED;
+#if defined(OS_CHROMEOS)
+    // Avoid saving to |saved_volume_percent_| if that is repeated pressing.

[Daniel Erat, 2016/07/28 04:45:00]

nit: delete this comment; the code is self-explanatory

+    if (!event->is_repeat()) {
+      chromeos::CrasAudioHandler* audio_handler =
+          chromeos::CrasAudioHandler::Get();
+      DCHECK(audio_handler->IsInitialized());

[Daniel Erat, 2016/07/28 04:45:00]

delete this too

+      saved_volume_percent_ = audio_handler->GetOutputVolumePercent();
+    }
+#endif
+  }
 }
 
 #if defined(OS_CHROMEOS)
 void PowerButtonController::OnDisplayModeChanged(
     const ui::DisplayConfigurator::DisplayStateList& display_states) {
   bool internal_display_off = false;
   bool external_display_on = false;
   for (const ui::DisplaySnapshot* display : display_states) {
     if (display->type() == ui::DISPLAY_CONNECTION_TYPE_INTERNAL) {
       if (!display->current_mode())
         internal_display_off = true;
     } else if (display->current_mode()) {
       external_display_on = true;
     }
   }
   internal_display_off_and_external_display_on_ =
       internal_display_off && external_display_on;
 }
 
 void PowerButtonController::PowerButtonEventReceived(
     bool down,
     const base::TimeTicks& timestamp) {
   OnPowerButtonEvent(down, timestamp);
 }
 #endif  // defined(OS_CHROMEOS)
 
+void PowerButtonController::TakingScreenshot() {
+  WmShell::Get()->accelerator_controller()->PerformActionIfEnabled(
+      TAKE_SCREENSHOT);
+}
+
 }  // namespace ash